Hot runner systems in injection molding machines include either mechanically gated nozzles (i.e., valve gated nozzles) or thermally gated nozzles (i.e., hot tip nozzles). Valve gating typically provides a better quality gate on the surface of the injection molded part. However, even valve gated nozzles can cause remnants of plastic to be left on the part after de-molding (e.g., crown flash or vestige). This vestige can be especially problematic with particular resins such as polypropylene.